Fossil find

Small fossils found in New Zealand will prompt a major rewrite of prehistory textbooks. The tiny fossilised bones belonged to a unique, mouse-sized land animal and were unearthed in a fossil bed in the Otago region of South Island. The fact that even one land mammal had lived there, at least 16 million years ago, has put paid to the theory that New Zealand’s rich bird fauna had evolved there because they had no competition from land mammals, researchers report in the journal Proceedings of the National Academy of Sciences.

Mice smell

Biologists at Washington University in St. Louis have discovered a large biological clock in the smelling centre of mice brains — the olfactory bulb — and have revealed that the sense of smell for mice is stronger at night, peaking in evening hours and waning during daylight hours. “The olfactory bulb might be more sensitive at night when the creatures are active than when they are resting in the day. This might help them find food or mates when they are hungry for food or for love,” the researchers write in the Journal of Neuroscience.

Stellar death

So far we have thought that the signature of the death of a massive star was an energetic explosion called a supernova. New observations show that this is not always the case. On the contrary, a team led by Danish researchers has now discovered that some massive stars die by collapsing into a black hole returning very little material into the interstellar medium. The discovery is published in the journal Nature. It is difficult to estimate what fraction of massive stars that die in this way, but it is probably small.